Lightweight construction has been a megatrend for many years – and not just in the automotive industry. Weight reductions in the vehicle body or vehicle components reduce energy consumption and thus CO2 emissions

Both automotive manufacturers and suppliers alike are thus permanently developing new technologies in the field of lightweight construction. Carbon composites are currently considered to be the most technically developed alternative. Compositence GmbH, based in the Swabian town of Leonberg, has developed a process for the production of carbon composites that not only dispenses with the need for the customary manufacture of semi-finished products, but also reduces trimmings to a minimum.

A KUKA KR 150 R3700 K ultra robot ensures the constantly reliable, high-quality feeding of the fibers to the laying head. Compositence’s patented manufacturing process has significant advantages not only for car production, however, but also for commercial vehicle, aerospace and wind power plant production.

The robot-based process increases productivity significantly, particularly for the production of parts with a large surface area

Markus Thiessen, Head of Sales & Marketing at Compositence

High production costs for CRP components

Carbon-fiber reinforced plastic (CRP) components are still predominantly handmade, resulting in both high material costs, due to the starting material and significant waste through trimmings, and also high process costs. This is because the first step in the production of large-area, high-performance composites is the manufacture of semi-finished products from carbon fibers, so-called rovings. These come in standard widths and standard fiber orientations. A component is then produced by cutting these semi-finished products to size and stacking them, tasks that are generally carried out manually.

A KUKA KR 150 R3700 K ultra robot ensures consistently high quality during take-off of the rovings or the thermoplastic tapes from the creel through to the feeding of the laying head at very high speed. The solution ensures consistently high quality coupled with minimized use of materials and, at the same time, increased lightweight potential due to the load-optimized design.

An optimal layup of the fibers makes the components lighter and thus even more attractive. Furthermore, the possibility of direct, three-dimensional application of the fibers opens up new flexibility in shaping.

The robot coats the component with carbon fibre directly at express speed and very high quality

Accuracy and efficiency also at high payloads

The KUKA KR 150 R3700 ultra K offers cycle times that are up to 25 percent shorter, fast acceleration, maximum path accuracy and high energy efficiency even in the high payload ranges. With a weight of just 1,215 kilograms, a long reach of 3,700 millimeters and a payload capacity of 150 kilograms, the KR 150 R3700 ultra K achieves a remarkable pose repeatability of less than 0.06 millimeters. At Compositence, it works together with a mobile turntable. The robot is controlled by a higher-level PLC.

Increase in productivity pays off

Existing automation solutions that automate the forming of semi-finished products would have reduced process times significantly, but this would have been offset, in most cases, by the major disadvantage of high investment costs and high levels of waste due to trimming. The Compositence process, on the other hand, enables direct layup of the carbon fibers to form the component with very little waste due to trimming.

As far as Compositence is concerned, this decision has long since paid off: the new development for thermoplastic tapes has also aroused great interest and already been sold to a number of customers. Furthermore, the system is also being adapted for alternative fiber materials and optimized for component-specific requirements.